1. Field of the Invention
The present invention relates to an electromagnetic wave shielding interior material which is enabled to obviate hazards pertinent to an electromagnetic wave such as malfunctions of or disturbances against various types of electronic instruments represented by computers caused by an electromagnetic wave, or adverse effects on human bodies of an electromagnetic wave which is especially being given attention in recent years.
2. Description of the Prior Art
A working process for giving an electromagnetic wave shielding property in the scale of a building is applied to an electromagnetic wave shield room for research purpose, medical facilities and the like, and at present a working process of integrating metal sheets by welding is generally used. However, this working process necessitates to carry out interior finishing separately, and so, in the future a working process having general availability which takes finishing property and economy into consideration is required, to say nothing of the above-described field of use, in the use including an inteligent building or a high technique factory for which expansion of demand is expected.
However, in the construction of an electromagnetic wave shield room in the prior art, a construction formed by integrating metal sheets through welding or the like was a common practice, and normally finishing was not especially taken into consideration. And it is the present status that in the case where demand for finishing simultaneously with construction of the electromagnetic wave shielding wall exists, the finishing work is carried out separately.
On the other hand, in the case of paying attention to an interior finish material, the interior finish sheet in the prior art had almost no electromagnetic wave shielding property, and as a method for giving electromagnetic wave shielding property while maintaining finishing property, although practically performed examples are scarce, as a countermeasure, the methods as enumerated in the following (a)-(f) are employed:
(a) application of electrically conductive paint, PA1 (b) metal spraying to a finish material, PA1 (c) metal vapor deposition to a finish material, PA1 (d) mixing of electrically conductive filler into a finish material, PA1 (e) mixing of electrically conductive fibers into a finish material, and PA1 (f) sticking a metal foil to a finish material.
Among the construction methods of an electromagnetic wave shield room in the prior art, the method of integrating metal sheets by welding involved problems in that a finishing property was almost not taken into consideration and a finishing work had to be carried out separately, in view of a term of construction as well as economy.
In addition, with regard to the above-mentioned methods (a)-(f) for giving an electromagnetic wave shielding performance to an interior finish material, according to the methods (a), (b) and (c), faulty portions are liable to be produced in the process of uniformly carrying out painting or vapor deposition, and so, distribution is apt to occur in the electromagnetic wave shielding performance. Also, as to the methods (d) and (e) a considerable amount of mixing is required for the purpose of revealing a predetermined electromagnetic wave shielding performance and moreover it is difficult to make the mixed substance disperse uniformly, resulting in that partly the electromagnetic wave shielding performance is liable to be degraded.
As to the method (f), while a copper foil and an aluminium foil are available as non-ferrous metal, in order to exhibit an electromagnetic wave shielding performance, a thickness thicker than a certain extent becomes necessary, and so, there was a problem in view of its cost as well as its handling. In addition, while an iron foil is excellent in an electromagnetic wave shielding performance as compared to the other non-ferrous metals having an identical thickness, in the case of the conventional rolled iron foil, it is difficult to obtain a uniform thin foil having flexibility, and hence there was a problem in manufacture.